Electromagnetic stepping mechanism for numeral wheels



Dec. 30, 1947. HANDLEY 2,433,608

ELECTROMAGNETIC STEPPING MECHANISM FOR NUMERAL WHEELS Filed July ll, 1944 Q QM MQM M Patented Dec. 30, 1947 UNITED 1 STATES PATEN OFF! c E i 2,433,608 rLEo'rnoMAGNETic sT P iNG MECHANISM."

FOR NU tWHEE AS, John Handley; London, England assignori to The Union Totalisator Compar'iyLi'mited, Glasgo'wg' Scotland, a company of Great Britain" Application July 11,1944, seriaLNq. 544,316) In Great Britain June l, 19 43] 1 Claim.

This invention relates to improvements in electromagnetic S pp ng mechanism for numeral wheels, particularly for use on totalisators, and concerns means for actuating such indicators by electric impulses so that the indicators will step in sequence with a master switch or a master indicator.

According to the invention a rotor element of the indicator is given step-by-step rotation partly by impulses from an electro-magnet, and partly by cam and spring means.

In one embodiment of the invention the indicator is in the form of a drum constituted of moulded artificial resin or other non-magnetic material, and provided with say ten inserts of magnetic material moulded into its rim.

An electro-magnet is so disposed that, when energised, it attracts one of the inserts, causing the drum to perform a partial rotation of approximately fifteen degrees.

The drum is so moulded as to present on one side a cam with ten peaks, and a spring-biased roller engaging the cam causes further rotation of the drum until the roller rests in a root between two peaks when the magnet is de-energized.

An indicator according to the invention is illustrated in the accompanying drawing in which Fig. 1 is a front elevation and Fig. 2 is a vertical section at right angles to Fig. 1.

Referring to the drawing, the indicator shown comprises three units A, B and C, respectively. Each unit bears numerals 0 to 9 and includes a rotor or drum l0 constituted of moulded artificial resin such as Bakelite and provided with soft iron peripheral inserts ll. Integral with the drum I0 is a cam wheel l2 presenting quick lift cams [2 tracked by a spring-urged roller l3.

For initiating each step of rotation of the drum there is used an intermittently energised electromagnet l4. When the electro-magnet is energised, the insert ll nearest the magnet is attracted and the drum I0 is partially rotated until the roller l3 has passed the peak of the respective cam, so that, when the magnet is de-energised, the drum rotates until the roller settles in the next cam root, leaving the next insert II in position ready to be attracted on the'next impulse.

The peaks of the cam are each shaped to have a quick lift on one side and a slow drop on the other side, the angle from the root center to the top of the peak being about twelve degrees, and from the peak to the next root about twentyfour degrees. With the peaks of the cams being thus formed a quick lift is initially imparted to the spring-urged roller, and the roller after passing the top of a peak exerts its rotative force on a substantially less inclined portion of the peak so that any danger of overrun of the cam is eliminated or minimized. That is particularly important in indicators of certain types. The magnet is so disposed that, when it is energised and has attracted an insert to a position centrally between its pole faces, the roller has passed over the peak by about three degrees. When the pulse has ceased, the drum will rotate twenty-one degrees until the roller is in the next root. In this position the magnet will be fifteen degrees in advance of the next insert, and twentyone degrees behind the insert which has just been attracted.

Each magnet I5 is bent into U-shape, and is attached to a bracket It by screws 21 and a distance piece 20, both of non-magnetic material. The spring 22 is attached to the bracket l6 by screws 23. The whole assembly is attached to a base plate H.

The drums l0 rotate on a spindle I8 supported by brackets I9.

The impulse and battery leads are attached to coil terminals 24 and 25.

This construction is primarily intended for a miniature indicator for clubs or betting booths, displaying a figure of about a one inch or two inches, and moving slowly in unison with a large public display indicator, Where there will be time for it to settle after each operation.

If preferred, the rotor may be made with a fewer number of inserts and cam peaks, and geared to a separate indicator drum, or may be used to drive a band indicator showing a numeral on the fiat.

The mechanism for rotating the drum is practically silent in operation.

What is claimed is:

A public indicator including a stepwise unidirectionally rotatable element of non-magnetic material having circumferentially-spaced, inserts of magnetic material presenting with the body of said rotatable element a continuous surface of revolution bearing spaced numerals on its periphery, an electro-magnet so positioned relatively to said rotatable element that when intermittently energized it will attract said inserts serially to effect the first part of each step of rotary movement of said rotatable element, and cam and spring means for effecting the final part of each step of rotary movement of said element, said rotatable element being unitary with said cam, said cam presenting a series of peaks and intermediate roots, and a roller carried by the spring and urged to engage said cam, the cam being so shaped that the angle from a root center to the top of the next peak, in the direction counter to the direction of rotation, is substantially greater than from the top of said peak to the next root center, whereby a quick lift is imparted to said roller and the roller, after passing the top of a peak, acts upon a less sharp incline on the following side of a peak to complete the step of rotary movement of the rotatable element and to prevent overthrow of the rotatable element, said roots being so positioned relatively to the inserts that after 5 each step of partial rotation of said element initiated by the electro-magnet influencing one insert and completed by the roller dropping into a root, the next following insert is in position to be attracted by the electro-magnet.

JOHN HANDLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 1 Number Name Date 380,594 Randall Apr. 3, 1888 474,614 Treat May 10, 1892 2,233,154 Welk Feb. 25, 1941 FOREIGN PATENTS Number I Country Date 1,228 Austria Apr. 25, 1900 287,074 Great Britain Mar. 7, 1929 

